what i can suggest is try a double combination, jump the first fence and then stop her, wait for a second then trot her to the second fence and do the same thing. try that a couple times and see how she responds. once you can get that down you can bump it up to a triple combo. this will get her to slow down and really work on listening to you so that she doesnt assume what you want, she waits for you to tell her. i used to have to do this with my gelding, if he hasnt been jumping in a while he does the same thing. also you can try when your trotting or cantering trot a couple steps and ask her to stop then trot a couple more steps then stop and ask her to back up, switch it up a bit so once again she's listening to you. once you master the trot work to the canter and do the same thing.
hope that helps!
"The horse you get off is not the same as the horse you got on; it is your job as a rider to ensure that as often as possible the change is for the better."